code: def test_region_serialized(self):
      self.trigger.region_name = "my_region"
      _, args = self.trigger.serialize()
  
      assert "region_name" in args
      assert args["region_name"] == "my_region"
  
file_path: airflow/tests/providers/amazon/aws/triggers/test_base.py
imports: from __future__ import annotations
  from typing import TYPE_CHECKING
  from unittest import mock
  from unittest.mock import MagicMock
  import pytest
  from airflow.providers.amazon.aws.triggers.base import AwsBaseWaiterTrigger
label_desc: Use image node_id 2 for calling the TestAwsBaseWaiterTrigger obj's underlying member method code with example usage: obj.test_region_serialized() without return types